Preparation of carboxylic acids from oxo alcohol esters



R, B. MASON Aug. 19, 1952 PREPARATION OF CARBOXYLIC ACIDS FROM OXOALCOHOL ESTERS Filed Aug. l, 1950 ZOBRU du .rom

alkyl, aryl ,or aralkyl:

Patented ug. 19, 1952 Ralph Burgess Mason, Baton Rouge, La.,`assignor Yto VStandard Oil Development' lCompany, a cor-.

poration of Delaware Applietin August 1, 1950, serial No. 176,975

Y. l Y. ,i- 1.1:. Il f This invention relatesjgenerally nto a l methodfor the synthesisgof fatty acidsv from olefms and speciiicallyrto 'animproved method for fatty acid synthesisjin which 'thereactions are'carried out in aA stepwise fashion, whereby more efcient conversion ofthe l olefin to fatty acid isl accomplished l A lAni improved'methodhasbeen ydiscovered for the Vsynthesis of fatty acids from oleiins whichcomprises conducting the over-all synthesis Y reaction in stages. Thus,the desired olerior its "Ox'o alcohol derivative isreactedwithpreviously fornied fatty acid` to produce anV ester; 1 Theesters are then reactedwith carbon monoxide to give a carboxylatedproduct including the acid It has been known that fatty acids-.Can be y6/ Claims. (Cl. 2611-413) Vprepared from straight-'chain olefinichydrocary bons by reaction of these' unsaturated hydrocarbons withcarbon monoxide and steam. The synthesis of aliphatic acids inV thisfashion is commonly carried out by a one-step process in the presence-ofaf catalyst. Catalysts which have been variously proposed for the acidsynthesis include various-metals yand metal carbonyls, as

well as acidic' catalysts such as halogen deriva.-

tives'of boron, for instance, boron fiuoride. The

reaction may be represented by the following generalized equation; inwhich Rmay be hydrogen,

" It has `been found experimentally, however,

that certain olens, principally branched Ca-Cis olens, do not reactappreciably with CO and Hz in' the presence. of metal carbonylcatalysts. Thus,` the branched chain olefinic polymers have to betreated in a different manner, as willbe Idescribed-in more detail,tovobtain fatty acids -The inherent unreaetivenature "of the highermolecular weight branched chain olens as the polymerized ethylene,propylene, and butylene fractions can be overcome, and very muchimproved yields of organic acidscan bei obtained using olen streams by'carrying out the synthesis reaction in stages; The effect is especial-Ester Carbon Acid anhydride monoxide R-C-o-ch-.R zia- Coon Y A1|4 V(H):Y Acid anhydridev v Acid The feed used in this stepwise ,process may'Ybe either the olefin itself or it may be an alcohol obtained fromgtheolen byan Oxo -type synthesis reaction.` Thealcohol'used should .containone less`v carbon atomfthan the acid being produced,`f and, in turn',thefolen used should have` one less carbonatom than the alcohol in orderto avoid production of mixtures of acids. In the Oxosynthesis, theolefin is first subjected to an oxonation with carbon monoxide andhydrogen to produce an Oxo' aldehyde product which issubsequentlyconverted tothe correspondingv Oxo alcohol by catalytichydrogenation. It is preferred to employ the Oxo alcohol as the startingmaterial, since in this way the inal acid product has one 4more carbonatom than does the acid productmade Afrom-the olen feedv directly. "Thealternate choice ofl feed serves to make the lover-all proces/sa exibleone. Furthermore, the ease and vconvenience of using ,comparative runs'm 'samc'ibzen'ici fear, cli-Lc polypropylene 13. 1?. asti-430 Fmg Mild.FGSI'- v'Treat and i' Carboxyla- Treatment y 'tion Y Pressure, p. s. ig. Temperature, F. i Hours of Bunn.; Product:

lPromoted'nickelcarbonyl.f f 7 The yieldsl obtainedin runIIlf infwhich.the

reaction was carried out in stages aresignificantly above those obtainedin a single stage operation where little or no yield was obtained.Further, it is of note that in run III, no purification or separation ofproducts'was employed A-between the various stages. Nevertheless,substantial yields ofithen'al acidwere' obtained.

The over-all process will be readily understood by the vfollowingdescription of a specic embodiment Which'shouldbe'read inconjunctionwith the accompanying diagrammatic outline of the various stages of theprocess.

An Oxo alcohol, such as is prepared from a C12-C13 polypropyleneoleflnic fraction is passed by line I into a closed esterication reactor3. A catalytic amount (about 2 to 10 wt. per cent) oi sulfuric acid isadded to reactor 3 via line 2. In reactor 3, the alcohol is contactedwith either recycled fatty acid produced during the operation or a partof the anhydride intermediate can be employedas a source of acid for theesterication. Esterication reactor 3 is suitably supplied with heatingmeans to maintain temperatures of about 200 F. Essentially atmosphericpressures are employed for the liquid phase esterification. 'I'he acidand alcohol should be contacted for a time suiiicient to accomplishsubstantially complete esterication.

The total reaction products, including the ester and the unusedcatalyst, are passed by lines 5 and 6 into acid synthesis reactor 9. Thefeed to this reactor includes about 5 to 15 wt. -per cent Ni(CO)4 addedby lines I :and 8r as catalyst and an appropriate amount of water addedby line 22. The reactor may desirably be constructed with a copperlining or a small :amount of a copper or nickel salt may be added sincecopper and nickel serve to act as .promoters for the carboxylation. Theratio of initial olefin employed -to water to catalyst preferred isabout l/ 1.35/03. A sufcient amount of carbon monoxide gas (about 95%purity) is added continuously by lines 2l and 8 to reactor =9 tomaintain a pressure of about 4000 p. s. i. g. Temperatures of around 550F. are employed for the carboxylation. After a greater part oi the esteris carboxylated to give products including anhydride, the totalcarboxylated products are passed by lines II4 and I2 to hydrolysis zoneI4. The gases, including N1(CO)4 and excess CO, are recycled by lines I0and :E 'backto acidsynthesis reactor' 9. At least a part of thecarboxylated product may be recycled vdirectly back', esterliication'reactor'.

l n The recycl'ejof a "partl'of' the"an`hydride productis of.especial..'usefulnefs'when 'a'fpart of the` initialThecarboxylatedproduct; `.passed vby .linejl'2v to hydrolysis,v zone,I4, 1s icon'tactedwith walter intro:- ducedinto zone 14IV byglirie y.Is. :The hydrolysis zone I-Ij'l is operatedl at about atmosphericpr'esj.-

sur@ Thwonefsbould :be equippedror suitable "heting'at" temperatures "of400500 The exact temperature employed in hydrolysis zone I4 will dependupon residence time of thecarboxylated product within the reactor. Thehydrolyzed acid and water mixture is passed by means portion of the acidis recycled through line 20' back to esterification reactor 3 toesterify additional alcohol and continue the process.

What is claimed is:

1. A method for preparing higher molecular weight, aliphatic carboxylicacids of the branched chain type, which comprises subjecting a mixtureof Oxo alcohols derived from an olen stream consisting predominantly ofbranched chain olens of the Cs-Cie lrange to an esterication With highermolecular Weight aliphatic carboxylic acids in the presence of anesterication catalyst, whereby there is produced a mixture consistingpredominantly of organic esters, subjecting said mixture of organicesters to a carboxylation reaction with carbon monoxide in the presenceof a carboxylation catalyst, thereafter subjecting the carboxylatedorganic product so produced t0 hydrolysis, and recovering highermolecular weight, aliphatic carboxylic acids of the branched chain typefrom the hydrolyzed mixture.

2. A method for the preparation of branched chain fatty acids whichcomprises reacting a mixture oi Oxo alcohols derived from an olefinstream consisting predominantly of branched chain oleins of the Cs-Ciarange with a part of the previously formed fatty acids in the presbythere'is produced a mixture of organic. esters,

-.u.ctconiafi,ning acid .anliydrides hydrohzing the lcarlooxylatedproduct to` acrnixture of fatty acids,

. contacting a part Vof vsaid fatty acids so produced passing theresulting mixture of organic esters with fresh A-Oxo alcohol toproducean additional to a. carboxylation zone, carboxylating said mix-` ture oforganic esters with carbon monoxide in j, e.

the presence of a metallic carbonyl carboxylation catalyst attemperatures in the range of 200700 F. and at superatmospheric pressuresin the range of 1,000 to 6,000 p.s./i.,g., whereby the i organic estersare substantially carboxylated to give a mixture containing 'organicacide VanefY hydrides, hydrolyzing the said carboxylated product to amixture of fatty'acids, and recov-r ering at least a part of said fattyacids from the hydrolyzed mixture. Y

V3. A process according to claim 2 in which the esteriflcation catalystis asmall amount of sulfuric acid and the carboxylation catalyst is'nickel carbonyl.

4. A process laccording to claim 2 in which the esterifcation catalystis boronr-trifluor-ide Vand the carboxylationcatalyst is nickelcarbonyl.

5. A method for the preparationfof C14-Cia fatty acids' "which comprisesreacting a lmixture vofljOxor alcohols derived 'by the 'OXo process from.a` Cia-:C1371,polypropylene ole'nf` stream with a 'parto'fjtlrepreviou'sly' formed ClT-Crsir'fatty lacids in the presence 'of4a catalyticgamount ofjsulfuri'c Aacid at a temperature f about200F'toiproduoe an."este'ie'd'organVA product "thereafter consaid estriiiedrganijch product Withcar- I e noxideinfthe pesencefja nickel carbonyl'ataly 'er ataVv emperature' of aboutl 1551? about 4,000

A esteriedproducm and recovering the remaining part ,of the resultingC14-C15 fatty acids.

6. A :method for the preparation of a higher molecula'rr'weightLaliphatic carboxylic acid 'of 41,0thebranched nchain type whichcomprises subjecting an Oxo alcohol derived, from an olefin streamconsistingy predominantly of a branched 'chainolefln having from 8 to1-6 carbon atoms, to an4 esterification with ra higher :molecular 15Weight 'aliphatic `carboxylic acid havingl one more carbon atomfthantheOxo alcoholfinth'e presence of an esteriilcation catalyst, lwherebythere is produced an organic ester, subjecting said organic ester to acarboxylationreaction with carbon monoxidein the .presence of acarboxylation catalyst, subjecting theresulting carboxylated organicproduct so produced no1-hydrolysis,

Vvand recovering a higher molecularV weight aliphatic carboxylic acidofrthebranched chain V type having one morevcarbon atom than the,'OXoa'lcohol from V'the hydrolyzed mixture.

The'followingrezferences are ,of record inthe i RALPTi-I BURGEss Meson.

2. A METHOD FOR THE PREPARATION OF BRANCHED CHAIN FATTY ACIDS WHICHCOMPRISES FROM AN OLEFIN MIXTURE OXO ALCOHOLS DERIVED FROM AN OLEFINSTREAM CONSISTING PREDOMINANTLY OF BRANCHED CHAIN OLEFINS OF THE C6-C16RANGE WITH A PART OF THE PREVIOUSLY FORMED FATTY ACIDS IN THE PRESENCEOF AN ACIDIC ESTERIFICATION CATALYST AT A TEMPERATURE IN THE RANGE OF150*-300* F., WHEREBY THERE IS PRODUCED A MIXTURE OF ORGANIC ESTERSPASSING THE RESULTING MIXTURE OF ORGANIC ESTERS TO A CARBOXYLATON ZONE,CARBOXYLATING AND MIXTURE OF ORGANIC ESTERS WITH CARBON MONOXIDE IN THEPRESENCE OF THE METALLIC CARBONYL CARBOXYLATION CATALYST AT TEMPERATURESIN THE RANGE OF 200*-700* F. AND AT SUPERATOMOSPHERIC PRESSURES IN THERANGE OF 1,000 TO 6,000 P.S.I.G., WHEREBY THE ORGANIC ESTERS ARESUBSTANTIALLY CARBOXYLATED TO GIVE A MIXTURE CONTAINING ORGANIC ACIDANHYDRIDES, HYDROLYZING THE SAID CARBOXYLATED PRODUCT TO A MIXTURE OFFATTY ACIDS, AND RECOVERING AT LEAST A PART OF SAID FATTY ACIDS FROM THEHYDROLYZED MIXTURE.